1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method and an apparatus for transmitting a symbol repeatedly.
2. Related Art
In a wireless communication system, a research for providing services of various qualities of service (QoS) having a high transmission rate to users is in active progress. In a wireless local area network (WLAN) system as one example of the communication system, a research into methods for transmitting a large amount of data at high speed and in a stable through a limited resource. In particular, in the wireless communication system, a research into transmission of data through a wireless channel is in progress. In recent years, methods for the WLAN system to, normally transmitting and receiving a large amount of data by effectively using a limited wireless channel have been proposed.
Further, the wireless communication system uses a high-order modulation method and more carriers in a limited frequency band in order to improve a data transmission rate and a throughput and uses a method for reducing the length of the symbol. A service area can be extended by acquiring a diversity effect through repeating the symbol and a signal reaching distance increases as the number of symbol repetition times, while the data transmission rate decreases. That is; the signal reaching distance and the data transmission rate has a trade-off relationship.
Meanwhile, the large amount of data, for example, a data packet transmitted and received through the wireless channel in the communication system includes a data field including the data transmitted and received through the wireless channel and a signal field including information on the data field. In the communication system, it is checked whether the signal field is normally checked and thereafter, data included in the data field is normally transmitted and received according to whether the signal field is normal.
However, since transmitted power of the wireless communication system is limited due to frequency limitation, the system design conditions improve the data transmission rate, while the signal reaching distance is limited, and as a result, improvement of the limit of the signal reaching distance is required.